Arrival direction estimation device

Abstract

To provide an arrival direction estimation device capable of estimating an arrival direction of radio waves flexibly and more accurately.SOLUTION: An arrival direction estimation device 100 estimates an arrival direction of radio waves transmitted from a base station. The arrival direction estimation device 100 comprises a plurality of antennas 101 to 104, a plurality of amplifiers 131 to 134, a plurality of phase shifters 141 to 144, a power measurement unit 112, a correlation matrix calculation unit 113, and an estimation unit 114. The plurality of amplifiers 131 to 134 amplify radio waves received by the antennas. The plurality of phase shifters 141 to 144 adjust phase amounts of the radio waves amplified by the amplifiers. The power measurement unit 112 measures power values corresponding to the gains of the plurality of amplifiers 131 to 134 and the phase amounts of the plurality of phase shifters 141 to 144. The correlation matrix calculation unit 113 calculates a correlation matrix value indicating the correlation between the plurality of antennas based on the power values. The estimation unit 114 estimates an arrival direction of the radio waves based on the correlation matrix value.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an arrival direction estimation device and an arrival direction estimation method. [Background technology]

[0002] Conventionally, in wireless communication, techniques have been proposed to estimate the direction in which the communication partner is located by estimating the direction of arrival of radio waves. Patent Document 1 discloses a direction estimation method using a beacon device. The direction estimation method disclosed in Patent Document 1 estimates the direction and position of the communication terminal device based on a correlation matrix calculated based on the propagation channel between the antenna and the communication terminal device. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2017-216567 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] The direction estimation method disclosed in Patent Document 1 uses a 180-degree hybrid element and a 90-degree hybrid element to estimate the direction of arrival based on a correlation matrix calculated based on the power of radio waves received by three antenna elements. In this direction estimation, the accuracy of the estimation improves with a larger number of antenna elements. However, the direction estimation method disclosed in Patent Document 1 is an estimation method using a 180-degree hybrid element, a 90-degree hybrid element, and a fixed setup with three antenna elements, and cannot address the need to further improve the estimation accuracy.

[0005] This invention has been made in view of the problems of the prior art described above. The object of this invention is to provide an arrival direction estimation device that can flexibly and more accurately estimate the direction of arrival of radio waves. [Means for solving the problem]

[0006] An approach direction estimation device according to an aspect of the present invention is an approach direction estimation device for estimating the approach direction of radio waves transmitted from a base station, comprising: a plurality of antennas for receiving radio waves transmitted from a base station; a plurality of amplifiers connected to each of the plurality of antennas and for amplifying the radio waves received by the antennas; a plurality of phase shifters connected to each of the plurality of amplifiers and for adjusting the phase amount of the radio waves amplified by the amplifiers; a power measurement unit that measures power values ​​corresponding to the gain of the plurality of amplifiers and the phase amount of the plurality of phase shifters and stores them in a memory unit; a correlation matrix calculation unit that calculates a correlation matrix value showing the correlation relationship of the plurality of antennas based on the power values; and an estimation unit that estimates the approach direction of radio waves based on the correlation matrix value.

[0007] Another aspect of the present invention relates to a method for estimating the direction of arrival of radio waves transmitted from a base station, which is performed by a computer and involves receiving radio waves transmitted from a base station with a plurality of antennas, amplifying the radio waves received by the antennas with a plurality of amplifiers connected to each of the plurality of antennas, adjusting the phase amount of the radio waves amplified by the amplifiers with a plurality of phase shifters connected to each of the plurality of amplifiers, measuring power values ​​corresponding to the gain of the plurality of amplifiers and the phase amount of the plurality of phase shifters, calculating a correlation matrix value showing the correlation relationship of the plurality of antennas based on the power values, and estimating the direction of arrival of the radio waves based on the correlation matrix value. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide an arrival direction estimation device that can flexibly and more accurately estimate the direction of arrival of radio waves. [Brief explanation of the drawing]

[0009] [Figure 1] This diagram shows the configuration of a communication system to which the direction-of-arrival estimation device according to this embodiment is applied. [Figure 2]This figure illustrates power measurement in the direction of arrival estimation device according to this embodiment. [Figure 3] This is a diagram illustrating the estimated angle of arrival in this embodiment. [Figure 4] This figure shows an example of the positional relationship between the direction of arrival estimation device according to this embodiment and the base station. [Figure 5] This figure shows the angular spectrum obtained from the channel correlation matrix estimated by the direction of arrival estimation device according to this embodiment. [Figure 6] This figure shows the results of a computer simulation for estimating the direction of arrival at the mobile station in this embodiment. [Figure 7] This figure shows the angular spectrum obtained from the channel correlation matrix estimated by a computer simulation of the direction of arrival estimation in the mobile station of this embodiment. [Figure 8] This flowchart shows an example of the processing of the direction of arrival estimation device according to this embodiment. [Modes for carrying out the invention]

[0010] The direction of arrival estimation device 100 according to this embodiment will be described in detail below with reference to the drawings. Note that the dimensional ratios in the drawings are exaggerated for illustrative purposes and may differ from the actual ratios. In addition, in the following drawings, identical or similar parts are denoted by the same or similar reference numerals.

[0011] (Configuration of communication system 10) Figure 1 shows the configuration of a communication system 10 to which the direction of arrival estimation device 100 according to this embodiment is applied. As shown in Figure 1, the communication system 10 is composed of the direction of arrival estimation device 100 and a transmitting station 200. The communication system 10 may also further include a receiver or a re-radiating device 300. The transmitting station 200 corresponds to a base station.

[0012] In the present embodiment, the direction-of-arrival estimation apparatus 100 is an apparatus that estimates the direction of arrival of radio waves (wireless signals) transmitted from the transmitting station 200. The transmitting station 200 transmits wireless signals to each receiving station. For the wireless signal transmitted from the transmitting station 200, a high-frequency band wireless signal such as a millimeter wave that can use a wide bandwidth is applied for the purpose of increasing transmission capacity. Note that in the present embodiment, the direction-of-arrival estimation apparatus 100 corresponds to a receiving station.

[0013] The direction-of-arrival estimation apparatus 100 is configured to include a plurality of antennas 101 to 104 that receive radio waves transmitted from the transmitting station 200, a control unit 110, a storage unit 120, a directivity adjustment unit 130, and a power distribution unit 160. Note that in the present embodiment, the direction-of-arrival estimation apparatus 100 is configured to include four antennas.

[0014] In the present embodiment, the antennas 101 to 104 provided in the direction-of-arrival estimation apparatus 100 are configured as a 4-element equally-spaced linear array antenna. Also, as shown in FIG. 1, propagation channels h1 to h4 are assigned as propagation channels between the transmitting station 200 and each of the antennas 101 to 104.

[0015] The control unit 110 is a component that controls the functions provided in the direction-of-arrival estimation apparatus 100. Specifically, the control unit 110 includes a setting unit 111, a power measurement unit 112, a correlation matrix calculation unit 113, and an estimation unit 114 as functional components. Details of each of these functions will be described later.

[0016] Further, the control unit 110 may be configured as, for example, a general-purpose microcomputer. In this case, a computer program for causing the microcomputer to function as the direction-of-arrival estimation device 100 may be installed in the microcomputer. By executing the computer program, the microcomputer functions as a plurality of information processing circuits included in the direction-of-arrival estimation device 100. Note that the present embodiment shows an example in which a plurality of information processing circuits included in the direction-of-arrival estimation device 100 are implemented by software; however, it is of course also possible to prepare dedicated hardware for executing each information processing described below to configure the information processing circuits. Further, the plurality of information processing circuits may be configured by separate pieces of hardware.

[0017] Further, the control unit 110 operates based on a program (not shown) stored in the storage unit 120, and executes each function included in the control unit 110. Note that the program is not limited to being stored in the storage unit 120, and for example, may be configured to be stored in a ROM or the like (not shown) in the direction-of-arrival estimation device 100.

[0018] The storage unit 120 stores, as data, set values for the directivity adjustment unit 130. Further, the storage unit 120 stores, as data, power values measured by a power measurement unit 112 described later. Furthermore, the storage unit 120 stores, as data, matrix components (correlation matrix values) of a correlation matrix calculated by a correlation matrix calculation unit 113 described later.

[0019] Further, as described above, the storage unit 120 may store programs for each function executed in the control unit 110. Note that the data and programs stored in the storage unit 120 may be configured as physically or logically separated regions provided in a single storage device. Alternatively, the storage unit 120 for each data may be provided in a plurality of physically different storage devices.

[0020] The directional adjustment unit 130 is composed of a plurality of amplifiers 131 to 134, a plurality of phase shifters 141 to 144, and a combining unit 150. The plurality of amplifiers 131 to 134 are connected to the plurality of antennas 101 to 104, respectively, and amplify the radio waves received by the antennas 101 to 104. In this embodiment, "connected to each other" means a state in which the objects are connected one-to-one, as shown by the plurality of antennas 101 to 104 and the plurality of amplifiers 131 to 134 in Figure 1. The amplifiers 131 to 134 are variable gain amplifiers, and they amplify the received radio waves based on the gain of the amplifiers 131 to 134 set by the setting unit 111.

[0021] Multiple phase shifters 141-144 are connected to multiple amplifiers 131-134, respectively, and adjust the phase amount of the radio waves amplified by the amplifiers 131-134. Note that phase shifters 141-144 are variable phase shifters, and adjust the phase of the radio waves amplified by the amplifiers 131-134 based on the phase amounts of phase shifters 141-144 set by the setting unit 111. The combining unit 150 combines the output signals of phase shifters 141-144 and sends them to the subsequent power distribution unit 160.

[0022] The power distribution unit 160 distributes the power of the signal output from the directional adjustment unit 130. One portion of the signal distributed by the power distribution unit 160 is sent to the power measurement unit 112 of the control unit 110. The other portion of the signal distributed by the power distribution unit 160 is sent to other receivers or devices requiring a wireless signal input, such as the re-radiation device 300.

[0023] (Functions of the direction of arrival estimation device 100) Next, the functions of the control unit 110 will be described. As mentioned above, the control unit 110 includes a setting unit 111, a power measurement unit 112, a correlation matrix calculation unit 113, and an estimation unit 114.

[0024] The setting unit 111 sets the gain of each amplifier 131 to 134 and the phase amount of each phase shifter 141 to 144 in the directivity adjustment unit 130. Specifically, the setting unit 111 sets the gain and phase amount values ​​shown in Figure 2 in the order of the measurement numbers. In the example shown in Figure 2, the G1 gain to G4 gains represent the gains set for amplifiers 131 to 134, respectively. Similarly, the PS1 phase amount to PS4 phase amount represent the phase amounts set for phase shifters 141 to 144, respectively. In other words, the setting unit 111 sets multiple different patterns of gain and phase amount for amplifiers 131 to 134 and phase shifters 141 to 144, as shown in measurement numbers 1 to 8 in Figure 2.

[0025] Furthermore, in the example shown in Figure 2, the gains of G1 to G4 are equal to the gain G on and gain G off The following is set. Here, the gain G on and gain G off The gain G on >>Gain G off The relationship is such that the gain G on In this case, amplification in amplifiers 131-134 becomes effective.

[0026] Furthermore, in the example shown in Figure 2, the phase values ​​for PS1 to PS4 are set to 0, 90, and 180.

[0027] In the example shown in Figure 2, measurement number 1 indicates that the G1 gain and G2 gain of amplifiers 131 and 132 are G on As a result, amplifiers 131 and 132 become active. In this case, the phase amounts of PS1 and PS2 of the subsequent stages of amplifiers 131 and 132 are applied.

[0028] As shown in Figure 2, the gains of amplifiers 131-134 and the phase amounts of phase shifters 141-144 are set. The signals that have passed through amplifiers 131-134 and phase shifters 141-144 are combined in the combining unit 150 and sent to the power distribution unit 160. Subsequently, as described above, in the power distribution unit 160, one of the signals output from the directivity adjustment unit 130 is sent to the power measurement unit 112 of the control unit 110. On the other hand, the other signal distributed in the power distribution unit 160 is sent to other receivers or devices requiring a wireless signal input, such as the re-radiation device 300.

[0029] The power measurement unit 112 measures the power of the signal output from the directional adjustment unit 130 and sent via the power distribution unit 160, and stores it in the storage unit 120.

[0030] In this embodiment, the power measurement unit 112 measures power based on the following equations (1) to (8) in the patterns from measurement number 1 to measurement number 8 shown in Figure 2. The power values ​​for measurement numbers 1 through 8 are given by the following equations (1) through (8).

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[0031] That is, in the pattern indicated by each measurement number, the gain G on power is measured for amplifiers 131 to 134 based on the PS1 phase amount to PS4 phase amount of phase shifters 141 to 144. When the phase amount is 0 [deg], the corresponding propagation channels h1 to h4 are applied. When the phase amount is 180 [deg], negative propagation channels h1 to h4 are applied. Further, when the phase amount is 90 [deg], propagation channels h1 to h4 multiplied by imaginary unit j are applied.

[0032] A correlation matrix calculation unit 113 calculates a correlation matrix value indicating a correlation relationship between the plurality of antennas 101 to 104 based on the plurality of power values measured by a power measurement unit 112. Specifically, the correlation matrix calculation unit 113 calculates the correlation matrix represented by the following formula (9) based on the power measured by the power measurement unit 112. [Formula]

[0033] Here, for the propagation channels h1 to h4 in the matrix components of the above formula (9), the values represented by the following formulas (10) to (13) are applied. [Formula] [Formula] [Formula] [Formula]

[0034] Further, for α, β, γ, and δ in formula (9), values satisfying the following formulas (14) to (20) are applied. [Formula] [Formula]

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[0035] The estimation unit 114 estimates the direction of arrival of radio waves (wireless signals) from the transmitting station 200 based on the correlation matrix values ​​calculated by the correlation matrix calculation unit 113. In this embodiment, the estimation unit 114 estimates the direction of arrival using a general beamformer method. By using the beamformer method, the direction of arrival estimation device 100 can estimate the direction of arrival with a simple configuration that reduces the burden of implementation and calculation.

[0036] In the beamformer method, the received power P(θ) can be expressed using equations (21) to (23) below, based on the weight vector w(θ) and the channel correlation matrix shown in equation (9) above.

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[0037] In this embodiment, the method for estimating the direction of arrival from the correlation matrix is ​​not limited to the beamformer method. For example, the estimation unit 114 in the direction of arrival estimation device 100 may be configured to estimate the direction of arrival θ of the radio waves using a general direction of arrival estimation method such as the linear prediction method or the MUSIC method.

[0038] Furthermore, after the direction of arrival is estimated by the estimation unit 114, the setting unit 111 sets the gain of the amplifiers 131-134 and the phase amount of the phase shifters 141-144 based on the direction of arrival of the radio waves estimated by the estimation unit 114. This enables the direction of arrival estimation device 100 to perform appropriate directivity control based on the estimated direction of arrival.

[0039] For example, the setting unit 111 may perform directivity control based on a reference table as shown in Figure 3. In this embodiment, the reference table shown in Figure 3 is stored in the storage unit 120 in advance. In the reference table shown in Figure 3, directivity indices are assigned according to a predetermined range of the estimated arrival angle, and the gain of amplifiers 131 to 134 and the phase amount of phase shifters 141 to 144 are determined according to each directivity index. The setting unit 111 refers to the directivity index from the reference table according to the estimated arrival angle and sets the corresponding gain of amplifiers 131 to 134 and the phase amount of phase shifters 141 to 144.

[0040] Next, we will explain the simulation of arrival direction estimation using the arrival direction estimation device 100 with reference to Figures 4 to 7.

[0041] Figure 4 shows the positional relationship when the coordinates of the transmitting station 200 are (0,0) and the coordinates of the receiving station, the direction of arrival estimation device 100, are (30,-15). In other words, in the positional relationship shown in Figure 4, θ = 30 degrees.

[0042] Figure 5 shows the simulation results of the angular spectrum (estimated value) obtained by applying the beamformer method to the channel correlation matrix estimated by the arrival direction estimation device 100 in this embodiment, and the true angular spectrum (true value), in the positional relationship shown in Figure 4. As shown in Figure 5, the assumed angular spectrum and the true angular spectrum are in close agreement, and the direction of the maximum value shown in Figure 5, θ = 30 degrees, can be estimated as the arrival direction.

[0043] Figure 6 shows the results of a computer simulation of direction of arrival estimation when the direction of arrival estimation device 100 is moved as a mobile station. In the example shown in Figure 6, the receiving station in Figure 4 is moved from position (30,-40) to position (30,40) at a speed of 100 km / h, power is measured every 20 ms, and the direction of arrival is estimated using the beamformer method.

[0044] As shown in Figure 6, until the first eight measurements are taken, it is not possible to estimate all the matrix components of R(h1,h2,h3,h4), resulting in a large error in the estimated arrival angle. On the other hand, from the eighth measurement onward, the estimation can be adjusted to track the fluctuating arrival angle.

[0045] Figure 7 shows a comparison between the estimated angular spectrum and the true angular spectrum at time t=900ms in Figure 6, when the mobile station passes the position (30,-15). In the example shown in Figure 7, the propagation channel fluctuates due to the movement of the receiving station, so the error in the estimated angular spectrum is larger than in the example shown in Figure 5, but it generally matches the true angular spectrum. In the example shown in Figure 7, the direction of arrival is estimated to be θ=30 degrees, which is the direction of the maximum value.

[0046] (Outline of the processing flow of the arrival direction estimation device 100) Next, the processing flow in the direction of arrival estimation device 100 is shown using the flowchart in Figure 8. The series of operations of the direction of arrival estimation device 100 shown in the flowchart in Figure 8 begin when the direction of arrival estimation device 100 is activated and end when the work is completed. In addition, the flowchart in Figure 8 also ends when the power is turned off or when an interrupt occurs indicating the end of processing. Furthermore, in the following explanation of the flowchart, the same content as described in the above-mentioned explanation of the communication system 10 and the direction of arrival estimation device 100 will be omitted or simplified.

[0047] In step S801, the setting unit 111 sets the gain values ​​of amplifiers 131-134 and phase values ​​of phase shifters 141-144 of the directivity adjustment unit 130. Specifically, the setting unit 111 sets the gain and phase values ​​as shown in Figure 2 in the order of the measurement numbers. In the example shown in Figure 2, G1 gain to G4 gain represent the gains set for amplifiers 131-134, respectively. Similarly, PS1 phase value to PS4 phase value represent the phase values ​​set for phase shifters 141-144, respectively. That is, in step S801, the setting unit 111 sets multiple different patterns of gain and phase values ​​for amplifiers 131-134 and phase shifters 141-144, as shown in measurement numbers 1 to 8 in Figure 2. The process then proceeds to step S802.

[0048] In step S802, the power measurement unit 112 measures the power of the signal output from the directional adjustment unit 130 and sent via the power distribution unit 160, and stores it in the storage unit 120. Specifically, the power measurement unit 112 measures the power based on the above-mentioned equations (1) to (8) for patterns from measurement number 1 to measurement number 8 shown in Figure 2. After that, the process proceeds to step S803.

[0049] In step S803, the control unit 110 determines whether the power measurement for a predetermined pattern has been completed. In this embodiment, the predetermined patterns are the measurement numbers 1 to 8 shown in Figure 2.

[0050] In step S803, if the control unit 110 determines that the power measurement for a predetermined pattern has been completed (step S803: YES), the process proceeds to step S804. On the other hand, in step S803, if the control unit 110 determines that the power measurement for a predetermined pattern has not been completed (step S803: NO), the process returns to step S801 and repeats the process from step S801.

[0051] In step S804, the correlation matrix calculation unit 113 calculates a correlation matrix value showing the correlation between the multiple antennas 101 to 104 based on the multiple power values ​​measured by the power measurement unit 112. Specifically, the correlation matrix calculation unit 113 calculates the correlation matrix shown in equation (9) above based on the power measured by the power measurement unit 112.

[0052] In step S805, the estimation unit 114 estimates the direction of arrival of the radio waves (wireless signals) from the transmitting station 200 based on the correlation matrix values ​​calculated by the correlation matrix calculation unit 113. In this embodiment, the estimation unit 114 estimates the direction of arrival using a general beamformer method. By using the beamformer method, the direction of arrival estimation device 100 can estimate the direction of arrival with a simple configuration that reduces the burden of implementation and calculation. The estimation of the direction of arrival using the beamformer method is performed based on equations (21) to (23) described above.

[0053] As described above, the direction of arrival estimation device 100 according to this embodiment is a direction of arrival estimation device that estimates the direction of arrival of radio waves transmitted from a base station. The direction of arrival estimation device 100 comprises a plurality of antennas 101 to 104, a plurality of amplifiers 131 to 134, a plurality of phase shifters 141 to 144, a power measurement unit 112, a correlation matrix calculation unit 113, and an estimation unit 114. The plurality of amplifiers 131 to 134 amplify the radio waves received by the antennas. The plurality of phase shifters 141 to 144 adjust the phase amount of the radio waves amplified by the amplifiers. The power measurement unit 112 measures power values ​​corresponding to the gain of the plurality of amplifiers 131 to 134 and the phase amount of the plurality of phase shifters 141 to 144. The correlation matrix calculation unit 113 calculates a correlation matrix value that shows the correlation relationship of the plurality of antennas based on the power values. The estimation unit 114 estimates the direction of arrival of the radio waves based on the correlation matrix value.

[0054] As a result, the direction of arrival estimation device 100 can flexibly and accurately estimate the direction of arrival of radio waves by adjusting the gain of the amplifiers 131 to 134 and the phase amount of the phase shifters 141 to 144.

[0055] Furthermore, in the above-described embodiment, the direction of arrival estimation device 100 includes a setting unit 111 that sets the gain of amplifiers 131-134 and the phase amount of phase shifters 141-144. This setting unit 111 sets multiple different patterns of gain and phase amount for amplifiers 131-134 and phase shifters 141-144. The power measurement unit 112 measures the power value according to the pattern set by the setting unit 111. For example, by setting multiple different patterns of gain and phase amount as shown in Figure 2, it becomes possible to estimate the direction of arrival without using dedicated circuits such as 180-degree hybrid elements or 90-degree hybrid elements. As a result, compared to cases where dedicated circuits such as 180-degree hybrid elements or 90-degree hybrid elements are used, the direction of arrival estimation device 100 in this embodiment can reduce the number of circuits and power consumption.

[0056] Furthermore, after the direction of arrival is estimated by the estimation unit 114, the setting unit 111 sets the gain of the amplifiers 131-134 and the phase amount of the phase shifters 141-144 based on the direction of arrival of the radio waves estimated by the estimation unit 114. As a result, the direction of arrival estimation device 100 can be applied to a communication system as a receiver with the direction of arrival appropriately adjusted.

[0057] Furthermore, the estimation unit 114 may estimate the direction of arrival of radio waves using the beamformer method. This makes it possible for the direction of arrival estimation device 100 to estimate the direction of arrival with a simple configuration that reduces the burden of implementation and computation.

[0058] (Other embodiments) While embodiments have been described in detail with reference to the drawings, these embodiments are not limited to those described above. Furthermore, the components described above include those easily conceivable by those skilled in the art, and those that are substantially the same. Moreover, the configurations described above can be combined as appropriate. In addition, various omissions, substitutions, or modifications of the configurations can be made without departing from the spirit of the embodiments.

[0059] In the above-described embodiment, an example was shown in which the system consists of four amplifiers 131-134 connected to each of the four antennas 101-104, and four phase shifters 141-144 connected to each of the amplifiers 131-134. This configuration is not limited to the embodiment. For example, the direction of arrival may be estimated based on three amplifiers 131-133 and three phase shifters 141-143 connected to each of three of the four antennas 101-103. In this case, the angle θ0 may be estimated as the peak of the three angular spectra, and the phase of the directivity adjustment unit 130 may be set so that the directivity peak points to this angle.

[0060] In this case, to direct the peak of the directivity of an N-element linear array antenna at an angle θ0, if the wavelength is λ and the spacing between antenna elements is d, then the phase ψ of the nth element... n This is shown in equation (24) below.

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[0061] In this way, using equation (24) above, it becomes possible to estimate the direction of arrival using fewer amplifiers and phase shifters than the number of antennas. For example, in a direction of arrival estimation device 100 equipped with six antennas, the direction of arrival estimation may be performed using three amplifiers and three phase shifters, and based on the estimated result, the setting unit 111 may set six amplifiers and six phase shifters. Similarly, for example, in a direction of arrival estimation device 100 equipped with eight antennas, the direction of arrival estimation may be performed using four amplifiers and four phase shifters, and based on the estimated result, the setting unit 111 may set eight amplifiers and eight phase shifters. In this way, by estimating the direction of arrival using fewer amplifiers and phase shifters than the actual number of antennas, it becomes possible to reduce the estimation time and power consumption by reducing processing.

[0062] Furthermore, a computer program (direction estimation program) that causes a computer to execute the processing (direction estimation method) in the aforementioned direction estimation device 100, and a computer-readable recording medium on which the program is stored, are included within the scope of this embodiment. Here, the type of computer-readable recording medium is arbitrary. Moreover, the computer program is not limited to one stored on a recording medium, but may also be transmitted via telecommunication lines, wireless or wired communication lines, networks such as the Internet, etc.

[0063] The features of the direction of arrival estimation device 100 and the direction of arrival estimation method are described below.

[0064] The first embodiment of the direction of arrival estimation device 100 is a direction of arrival estimation device that estimates the direction of arrival of radio waves transmitted from a base station. The direction of arrival estimation device 100 includes a plurality of antennas 101 to 104 that receive radio waves transmitted from the base station. The direction of arrival estimation device 100 also includes a plurality of amplifiers 131 to 134 that are connected to each of the plurality of antennas 101 to 104 and amplify the radio waves received by the antennas 101 to 104. The direction of arrival estimation device 100 also includes a plurality of phase shifters 141 to 144 that are connected to each of the plurality of amplifiers 131 to 134 and adjust the phase amount of the radio waves amplified by the amplifiers 131 to 134. The direction of arrival estimation device 100 also includes a power measurement unit 112 that measures power values ​​corresponding to the gain of the plurality of amplifiers 131 to 134 and the phase amount of the plurality of phase shifters 141 to 144 and stores them in a storage unit 120. Furthermore, the direction of arrival estimation device 100 includes a correlation matrix calculation unit 113 that calculates a correlation matrix value showing the correlation between multiple antennas 101 to 104 based on power values. In addition, the direction of arrival estimation device 100 includes an estimation unit 114 that estimates the direction of arrival of radio waves based on the correlation matrix value.

[0065] With the above configuration, the direction of arrival estimation device 100 can flexibly and accurately estimate the direction of arrival of radio waves by adjusting the gain of the amplifiers 131 to 134 and the phase amount of the phase shifters 141 to 144.

[0066] The direction of arrival estimation device 100 according to the second embodiment may further include a setting unit 111 for setting the gain of amplifiers 131-134 and the phase amount of phase shifters 141-144. The setting unit 111 of the direction of arrival estimation device 100 may also set multiple different patterns of gain and phase amount for amplifiers 131-134 and phase shifters 141-144. Furthermore, the power measurement unit 112 of the direction of arrival estimation device 100 may measure power values ​​corresponding to the patterns set by the setting unit 111.

[0067] With the above configuration, the direction of arrival estimation device 100 can estimate the direction of arrival without using dedicated circuits such as 180-degree hybrid elements or 90-degree hybrid elements. As a result, the direction of arrival estimation device 100 can reduce the number of circuits and lower power consumption compared to cases where dedicated circuits such as 180-degree hybrid elements or 90-degree hybrid elements are used.

[0068] In the third embodiment, the setting unit 111 of the direction of arrival estimation device 100 may set the gain of the amplifiers 131 to 134 and the phase amount of the phase shifters 141 to 144 based on the direction of arrival of the radio waves estimated by the estimation unit 114 after the direction of arrival has been estimated by the estimation unit 114.

[0069] According to the above configuration, the direction of arrival estimation device 100 can be applied to a communication system as a receiver with an appropriately adjusted direction of arrival.

[0070] The estimation unit 114 of the direction of arrival estimation device 100 according to the fourth embodiment may estimate the direction of arrival of radio waves by the beamformer method.

[0071] According to the above configuration, the direction of arrival estimation device 100 can estimate the direction of arrival with a simple configuration that reduces the burden of implementation and computation.

[0072] The fifth aspect of the direction of arrival estimation method is a method performed by a computer to estimate the direction of arrival of radio waves transmitted from a base station. The direction of arrival estimation method includes the process of receiving radio waves transmitted from the base station using a plurality of antennas 101 to 104. The direction of arrival estimation method also includes the process of amplifying the radio waves received by the antennas 101 to 104 using a plurality of amplifiers 131 to 134 connected to each of the plurality of antennas 101 to 104. The direction of arrival estimation method also includes the process of adjusting the phase amount of the radio waves amplified by the amplifiers 131 to 134 using a plurality of phase shifters 141 to 144 connected to each of the plurality of amplifiers 131 to 134. The direction of arrival estimation method also includes the process of measuring power values ​​corresponding to the gain of the plurality of amplifiers 131 to 134 and the phase amount of the plurality of phase shifters 141 to 144. The direction of arrival estimation method also includes the process of calculating a correlation matrix value showing the correlation relationship of the plurality of antennas 101 to 104 based on the power values. Furthermore, the direction of arrival estimation method includes a process for estimating the direction of arrival of radio waves based on correlation matrix values.

[0073] With the above configuration, the direction of arrival estimation method can be performed flexibly and with greater accuracy by adjusting the gain of amplifiers 131-134 and the phase amount of phase shifters 141-144. [Explanation of Symbols]

[0074] 10 Communication Systems 100 Direction of arrival estimation device 101, 102, 103, 104 Antennas 110 Control Unit 111 Settings Section 112 Power Measurement Unit 113 Correlation Matrix Calculation Unit 114 Estimation Department 120 Storage section 130 Directivity adjustment section 131, 132, 133, 134 Amplifier 141, 142, 143, 144 Phase Element 150 Synthesis part 160 Power distribution section

Claims

1. An arrival direction estimation device for estimating the direction of arrival of radio waves transmitted from a base station, Multiple antennas that receive the radio waves transmitted from the base station, Multiple amplifiers are connected to each of the multiple antennas and amplify the radio waves received by the antennas, Multiple phase shifters, each connected to a plurality of amplifiers, adjust the phase quantities of multiple different patterns to which the propagation channel of the radio waves amplified by the amplifiers, the negative propagation channel of the radio waves, and the imaginary propagation channel of the radio waves are applied. A combining unit that combines the output signals of multiple phase transformers, A power measuring unit measures the power of a signal obtained by combining the output signals of a plurality of phase transformers, the power value corresponding to the pattern, and stores it in a storage unit. A correlation matrix calculation unit calculates a correlation matrix value that shows the correlation between multiple antennas based on the power values, An estimation unit that estimates the direction of arrival of the radio waves based on the correlation matrix values, A setting unit for setting the gain of the amplifier and the phase amount of the phase transformer, Equipped with, The correlation matrix calculation unit calculates the correlation matrix value indicating the correlation between the antennas, based on the power value of the signal obtained by synthesizing the output signal obtained by adjusting the phase amount of the radio waves amplified by the amplifiers, which are fewer than the number of antennas, with the phase shifters, which are fewer than the number of antennas. The estimation unit estimates the direction of arrival of the radio waves based on the correlation matrix values ​​that show the correlation of a number of antennas less than the number of antennas. The setting unit is an arrival direction estimation device that, after the arrival direction is estimated by the estimation unit, sets the gain of the amplifiers in a number corresponding to the number of antennas and the phase amount of the phase transformers in a number corresponding to the number of antennas, based on the arrival direction of the radio waves estimated by the estimation unit.

2. The direction of arrival estimation device according to claim 1, wherein the estimation unit estimates the direction of arrival of the radio waves by the beamformer method.

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